Over the years a lot of different VTOL (Vertical Take off and landing) configurations where tested. These configurations can be seen in, Seth B. Anderson, “Historic Overview of V/STOL Aircraft Technology,” NASA™ 81280, March 1981 (the site http://www.aiaa.org/tc/vstol/wheel.html as one copy of the implementation wheel of V/STOL aircrafts).
Most of these configurations were never used in commercial aircrafts. The different configurations can be classified in several possible ways, such as:                Same propulsion for hover and flight        Different propulsion for hover and flight        Augmented propulsion power for hover        
Each of these can be further divided in several subclasses like for example, wing Tilt, propeller tilt and so on.
The classification wheel does not include the helicopter. The helicopter is also a VTOL machine since it can also take off and land vertically, the difference to the VTOL wheel aircrafts being that the helicopter does not have fixed wings for providing all (or most) of the lift force for the aircraft when it moves forward.
Among all of these VTOL machines the helicopter (in all its different propulsion versions) is clearly the best commercial VTOL machine and the machine with more units throughout the world.
Among all the tested VTOL configurations merely five exist at present, most of them only in a military configuration, and these are as follows:                Helicopter (all versions included have the same propulsion for vertical and horizontal flight, with rotors),        the military Osprey V22 aircraft (same propulsion for vertical and horizontal flight, with tilt rotors),        the military jet Harrier (same propulsion for hover and flight, with vector thrust),        the military jet Yakovlev YAK-3B (different propulsion for hover and flight), and        the military jet Lockheed Martin X-35 (with a thrust increase system for hover, using a separate fan for VTOL operation).        
Among these commercial airplanes it can be easily seen that the only civil VTOL aircraft is the helicopter. In the near future the convertible Bell Augusta BA609, which is similar to the Osprey V22, will be certified.
There is a number of reasons for the lack of success of most of the tested configurations for a VTOL aircraft, some of the reasons being: Very difficult control of take off and landing, very difficult control of the transition phase from horizontal to vertical flight, high cost and complexity, instability problems, large weight of several engines for horizontal and vertical flight and large weight of large shafts and gears, slow controls response time (aggravating instability), transmission failures, very high vibration and so on.
Among the enumeration of the problems of VTOL aircrafts it can be seen that a large portion of the problems is related to control.
Normal aircrafts, from an aerodynamic control point of view, can be classified in regard to their independent control axis as:                One forward translation axis (power) and three rotation control axis—conventional airplane        Three translation axis, up or down (power), forward or backward and left or right (due to the cyclic pitch of the main rotor, but some rotation occurring also in the pitch axis or in the roll axis) and one rotational axis—Helicopter (all types including the not so conventional with two main counter-rotating rotors).        
Both of these configurations are not able to perform an independent control of three translation axes and three rotation axis.
Some built flying machines can, at least in theory, displace themselves according to most of the three translation and three rotation axis.
Among the previously referred VTOL wheel some aircrafts, like the Harrier, can, in the take-off (or landing) phase perform one translation and two rotations (pitch and roll axis) but only for a very short time.
It was previously mentioned that the helicopter comprises three translation axis, but in the helicopter and similar flying machines the translational displacement affects one of the rotation axis and as a result the translation displacements are not fully independent of the rotation axes.
When moving forward the conventional helicopter rotates also around the pitch axis, this meaning that the translation axis is not fully independent of the rotation axis, making it impossible for the helicopter to maintain the angle of the longitudinal axis with the horizon when moving forward or backward.
The existing patents do not cover the aforementioned problems, or just make some reference to them without proposing a feasible solution for a full vector three translational and three rotation axis control aircraft in a simple form.
In the case of spacecrafts there are solutions for this vector control, but the existing solutions are complex and demand large numbers of isolated thrusters.
The theoretically simple solution is to use two thrusters at the same distance symmetrically from Cg (Mass centre of aircraft) on the Y axis (lateral axis, right or left side), and two thrusters located on the X axis (front or back) and two more on Z axis. This configuration allows for a full vector aircraft control. However very costly because it requires the use of six equal thrusters or propellers, when actually most of the time only two will be used.
Several of the existing patents do not cover the problems mentioned previously, or just refer to them without achieving a complete solution for a full vector control (three translational and three rotation axis), thus allowing the implementation of a control algorithm that significantly increases the agility of the aircraft, spacecraft or vehicle moving in any fluid or vacuum, and reducing the external influence due to turbulence disturbances acting on the aircraft, thus increasing passenger comfort (in gust wind situations or others).
Patent U.S. Pat. No. 6,719,244 “VTOL AIRCRAFT CONTROL USING OPPOSED TILTING OF ITS DUAL PROPELLERS OR FANS” is a system using only two propellers counter-rotating without cyclic pitch-change using propellers tilting around two axis for counter acting the pitch axis change when the aircraft is moving forward. This cannot achieve full vector three translational and three rotational axes control.
Patent U.S. Pat. No. 6,607,161 “CONVERTIBLE AIRCRAFT WITH TILTING ROTORS” and similar patents U.S. Pat. No. 2,230,370 and U.S. Pat. No. 2,702,168 are convertible aircrafts with only two opposed rotors that only tilt forward and backward but not laterally, like the present invention.
Patent U.S. Pat. No. 3,106,369 “AIRCRAFT AND METHOD OF OPERATING SAME” has some similarities to the two tiltable main rotors (with cyclic pitch-change) and a jet which helps controlling aircraft pitch. Again, the aircraft does not tilt the main rotors around two axes, only one, and for moving laterally it uses the cyclic pitch-change. This cannot accomplish full vector three translational and three rotational axes control of the aircraft.
Patent U.S. Pat. No. 3,141,633 “TILT-WING AIRCRAFT” is a tilt wing aircraft and has a number of rotors on the wing with an additional located in the back for aircraft pitch control, it only moves the rotors in one axis, and again it cannot accomplish a full vector aircraft control.
Patent U.S. Pat. No. 6,708,920 “AIR VEHICLE” uses four main identical fans that are tiltable around two axes (roll and pitch.) This different from the present invention using two main thrusters or propellers or jets tilting around two main axes and two small auxiliary thrusters or propellers or jets fixed in their rotation axes. Other differences are the concern of patent U.S. Pat. No. 6,708,920 with the engine and fan shapes, positions and cooling thereof and not with the full vector ability (independent rotations of the vehicle are not predicted). The possibility to counteract gust and turbulences is not mentioned.
Patent U.S. Pat. No. 5,419,514 “VTOL AIRCRAFT CONTROL METHOD”, relates to a method of increasing the stability of a VTOL, aircraft, not being a full vector control method.
Patent U.S. Pat. No. 6,808,140 “VERTICAL TAKE-OFF AND LANDING VEHICLES” has a similar configuration but the main thrusters are aided by vanes that alter the air flow direction, and the main fans only rotate around the pitch axis (from the partially vertical position to full horizontal position parallel to flight direction). It cannot be full vector.
Patent U.S. Pat. No. 3,544,042 “AERODYNE WITH VERTICAL TAKE-OFF OR LANDING MEANS” uses a similar configuration but doesn't have auxiliary propellers for additional control, therefore it cannot be full vector.
Patent U.S. Pat. No. 1,851,764 “AEROPLANE” is a similar configuration, in some aspects, the main propellers being rotatable around two axis but these are always synchronized and cannot be tilted independently. This patent does not include auxiliary propellers or jets as the present invention.
Patent U.S. Pat. No. 6,892,980 “VERTICAL TAKEOFF AND LANDING AIRCRAFT” is, from a control point of view, similar to patent U.S. Pat. No. 6,708,920 but uses only one turbofan engine that drives the four two axis tiltable propellers and it has wings making it a convertible aircraft. The configuration described by this patent is a rectangle where the four tiltable propellers are placed in the corners. This placement and the identical four propellers or fans differ from the present invention. Nowhere in the patent is referred the possibility to counteract the influence of turbulence, thus allowing, the increase in passenger comfort. The aircrafts control is made by propeller or fan rotation and not by RPM (rotations per minute) changes or changes in the propeller pitch combined with the propeller or fans tilting, this differing from the present invention.
The present invention is intended to solve the aforementioned problems by using a propulsion central system according to claim 1. The additional embodiments will be apparent from the dependent claims.